'\" t
.TH "SD_PID_GET_OWNER_UID" "3" "" "systemd 257~rc3" "sd_pid_get_owner_uid"
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.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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.nh
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.ad l
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.\" * MAIN CONTENT STARTS HERE *
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.SH "NAME"
sd_pid_get_owner_uid, sd_pid_get_session, sd_pid_get_user_unit, sd_pid_get_unit, sd_pid_get_machine_name, sd_pid_get_slice, sd_pid_get_user_slice, sd_pid_get_cgroup, sd_pidfd_get_owner_uid, sd_pidfd_get_session, sd_pidfd_get_user_unit, sd_pidfd_get_unit, sd_pidfd_get_machine_name, sd_pidfd_get_slice, sd_pidfd_get_user_slice, sd_pidfd_get_cgroup, sd_peer_get_owner_uid, sd_peer_get_session, sd_peer_get_user_unit, sd_peer_get_unit, sd_peer_get_machine_name, sd_peer_get_slice, sd_peer_get_user_slice, sd_peer_get_cgroup \- Determine the owner uid of the user unit or session, or the session, user unit, system unit, container/VM or slice that a specific PID or socket peer belongs to
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-login\&.h>
.fi
.ft
.HP \w'int\ sd_pid_get_owner_uid('u
.BI "int sd_pid_get_owner_uid(pid_t\ " "pid" ", uid_t\ *" "uid" ");"
.HP \w'int\ sd_pid_get_session('u
.BI "int sd_pid_get_session(pid_t\ " "pid" ", char\ **" "session" ");"
.HP \w'int\ sd_pid_get_user_unit('u
.BI "int sd_pid_get_user_unit(pid_t\ " "pid" ", char\ **" "unit" ");"
.HP \w'int\ sd_pid_get_unit('u
.BI "int sd_pid_get_unit(pid_t\ " "pid" ", char\ **" "unit" ");"
.HP \w'int\ sd_pid_get_machine_name('u
.BI "int sd_pid_get_machine_name(pid_t\ " "pid" ", char\ **" "name" ");"
.HP \w'int\ sd_pid_get_slice('u
.BI "int sd_pid_get_slice(pid_t\ " "pid" ", char\ **" "slice" ");"
.HP \w'int\ sd_pid_get_user_slice('u
.BI "int sd_pid_get_user_slice(pid_t\ " "pid" ", char\ **" "slice" ");"
.HP \w'int\ sd_pid_get_cgroup('u
.BI "int sd_pid_get_cgroup(pid_t\ " "pid" ", char\ **" "cgroup" ");"
.HP \w'int\ sd_pidfd_get_owner_uid('u
.BI "int sd_pidfd_get_owner_uid(int\ " "pidfd" ", uid_t\ *" "uid" ");"
.HP \w'int\ sd_pidfd_get_session('u
.BI "int sd_pidfd_get_session(int\ " "pidfd" ", char\ **" "session" ");"
.HP \w'int\ sd_pidfd_get_user_unit('u
.BI "int sd_pidfd_get_user_unit(int\ " "pidfd" ", char\ **" "unit" ");"
.HP \w'int\ sd_pidfd_get_unit('u
.BI "int sd_pidfd_get_unit(int\ " "pidfd" ", char\ **" "unit" ");"
.HP \w'int\ sd_pidfd_get_machine_name('u
.BI "int sd_pidfd_get_machine_name(int\ " "pidfd" ", char\ **" "name" ");"
.HP \w'int\ sd_pidfd_get_slice('u
.BI "int sd_pidfd_get_slice(int\ " "pidfd" ", char\ **" "slice" ");"
.HP \w'int\ sd_pidfd_get_user_slice('u
.BI "int sd_pidfd_get_user_slice(int\ " "pidfd" ", char\ **" "slice" ");"
.HP \w'int\ sd_pidfd_get_cgroup('u
.BI "int sd_pidfd_get_cgroup(int\ " "pidfd" ", char\ **" "cgroup" ");"
.HP \w'int\ sd_peer_get_owner_uid('u
.BI "int sd_peer_get_owner_uid(int\ " "fd" ", uid_t\ *" "uid" ");"
.HP \w'int\ sd_peer_get_session('u
.BI "int sd_peer_get_session(int\ " "fd" ", char\ **" "session" ");"
.HP \w'int\ sd_peer_get_user_unit('u
.BI "int sd_peer_get_user_unit(int\ " "fd" ", char\ **" "unit" ");"
.HP \w'int\ sd_peer_get_unit('u
.BI "int sd_peer_get_unit(int\ " "fd" ", char\ **" "unit" ");"
.HP \w'int\ sd_peer_get_machine_name('u
.BI "int sd_peer_get_machine_name(int\ " "fd" ", char\ **" "name" ");"
.HP \w'int\ sd_peer_get_slice('u
.BI "int sd_peer_get_slice(int\ " "fd" ", char\ **" "slice" ");"
.HP \w'int\ sd_peer_get_user_slice('u
.BI "int sd_peer_get_user_slice(int\ " "fd" ", char\ **" "slice" ");"
.HP \w'int\ sd_peer_get_cgroup('u
.BI "int sd_peer_get_cgroup(int\ " "fd" ", char\ **" "cgroup" ");"
.SH "DESCRIPTION"
.PP
\fBsd_pid_get_owner_uid()\fR
may be used to determine the Unix UID (user identifier) which owns the login session or systemd user unit of a process identified by the specified PID\&. For processes which are not part of a login session and not managed by a user manager, this function will fail with
\fB\-ENODATA\fR\&.
.PP
\fBsd_pid_get_session()\fR
may be used to determine the login session identifier of a process identified by the specified process identifier\&. The session identifier is a short string, suitable for usage in file system paths\&. Please note the login session may be limited to a stub process or two\&. User processes may instead be started from their systemd user manager, e\&.g\&. GUI applications started using DBus activation, as well as service processes which are shared between multiple logins of the same user\&. For processes which are not part of a login session, this function will fail with
\fB\-ENODATA\fR\&. The returned string needs to be freed with the libc
\fBfree\fR(3)
call after use\&.
.PP
\fBsd_pid_get_user_unit()\fR
may be used to determine the systemd user unit (i\&.e\&. user service or scope unit) identifier of a process identified by the specified PID\&. The unit name is a short string, suitable for usage in file system paths\&. For processes which are not managed by a user manager, this function will fail with
\fB\-ENODATA\fR\&. The returned string needs to be freed with the libc
\fBfree\fR(3)
call after use\&.
.PP
\fBsd_pid_get_unit()\fR
may be used to determine the systemd system unit (i\&.e\&. system service or scope unit) identifier of a process identified by the specified PID\&. The unit name is a short string, suitable for usage in file system paths\&. Note that not all processes are part of a system unit/service\&. For processes not being part of a systemd system unit, this function will fail with
\fB\-ENODATA\fR\&. (More specifically, this call will not work for kernel threads\&.) The returned string needs to be freed with the libc
\fBfree\fR(3)
call after use\&.
.PP
\fBsd_pid_get_machine_name()\fR
may be used to determine the name of the VM or container is a member of\&. The machine name is a short string, suitable for usage in file system paths\&. The returned string needs to be freed with the libc
\fBfree\fR(3)
call after use\&. For processes not part of a VM or container, this function fails with
\fB\-ENODATA\fR\&.
.PP
\fBsd_pid_get_slice()\fR
may be used to determine the slice unit the process is a member of\&. See
\fBsystemd.slice\fR(5)
for details about slices\&. The returned string needs to be freed with the libc
\fBfree\fR(3)
call after use\&.
.PP
Similarly,
\fBsd_pid_get_user_slice()\fR
returns the user slice (as managed by the user\*(Aqs systemd instance) of a process\&.
.PP
\fBsd_pid_get_cgroup()\fR
returns the control group path of the specified process, relative to the root of the hierarchy\&. Returns the path without trailing slash, except for processes located in the root control group, where "/" is returned\&. To find the actual control group path in the file system, the returned path needs to be prefixed with
/sys/fs/cgroup/
(if the unified control group setup is used), or
/sys/fs/cgroup/\fIHIERARCHY\fR/
(if the legacy multi\-hierarchy control group setup is used)\&.
.PP
If the
\fIpid\fR
parameter of any of these functions is passed as 0, the operation is executed for the calling process\&.
.PP
The
\fBsd_pidfd_get_owner_uid()\fR,
\fBsd_pidfd_get_session()\fR,
\fBsd_pidfd_get_user_unit()\fR,
\fBsd_pidfd_get_unit()\fR,
\fBsd_pidfd_get_machine_name()\fR,
\fBsd_pidfd_get_slice()\fR,
\fBsd_pidfd_get_user_slice()\fR
and
\fBsd_pidfd_get_cgroup()\fR
calls operate similarly to their PID counterparts, but accept a
\fBPIDFD\fR
instead of a
\fBPID\fR, which means they are not subject to recycle race conditions as the process is pinned by the file descriptor during the whole duration of the invocation\&. Note that these require a kernel that supports
\fBPIDFD\fR\&. A suitable file descriptor may be acquired via
\fBpidfd_open\fR(2)\&.
.PP
The
\fBsd_peer_get_owner_uid()\fR,
\fBsd_peer_get_session()\fR,
\fBsd_peer_get_user_unit()\fR,
\fBsd_peer_get_unit()\fR,
\fBsd_peer_get_machine_name()\fR,
\fBsd_peer_get_slice()\fR,
\fBsd_peer_get_user_slice()\fR
and
\fBsd_peer_get_cgroup()\fR
calls operate similarly to their PID counterparts, but accept a connected
\fBAF_UNIX\fR
socket and retrieve information about the connected peer process\&. Note that these fields are retrieved via
/proc/, and hence are not suitable for authorization purposes, as they are subject to races\&.
.SH "RETURN VALUE"
.PP
On success, these calls return 0 or a positive integer\&. On failure, these calls return a negative errno\-style error code\&.
.SS "Errors"
.PP
Returned errors may indicate the following problems:
.PP
\fB\-ESRCH\fR
.RS 4
The specified PID does not refer to a running process\&.
.RE
.PP
\fB\-EBADF\fR
.RS 4
The specified socket file descriptor was invalid\&.
.RE
.PP
\fB\-ENODATA\fR
.RS 4
The given field is not specified for the described process or peer\&.
.RE
.PP
\fB\-EINVAL\fR
.RS 4
An input parameter was invalid (out of range, or
\fBNULL\fR, where that is not accepted)\&.
.RE
.PP
\fB\-ENOMEM\fR
.RS 4
Memory allocation failed\&.
.RE
.SH "NOTES"
.PP
Functions described here are available as a shared library, which can be compiled against and linked to with the
\fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
file\&.
.PP
Note that the login session identifier as returned by
\fBsd_pid_get_session()\fR
is completely unrelated to the process session identifier as returned by
\fBgetsid\fR(2)\&.
.SH "HISTORY"
.PP
\fBsd_peer_get_cgroup()\fR,
\fBsd_peer_get_machine_name()\fR,
\fBsd_peer_get_owner_uid()\fR,
\fBsd_peer_get_session()\fR,
\fBsd_peer_get_slice()\fR,
\fBsd_peer_get_unit()\fR,
\fBsd_peer_get_user_slice()\fR,
\fBsd_peer_get_user_unit()\fR,
\fBsd_pid_get_cgroup()\fR,
\fBsd_pid_get_machine_name()\fR,
\fBsd_pid_get_owner_uid()\fR,
\fBsd_pid_get_session()\fR,
\fBsd_pid_get_slice()\fR,
\fBsd_pid_get_unit()\fR,
\fBsd_pid_get_user_slice()\fR, and
\fBsd_pid_get_user_unit()\fR
were added in version 236\&.
.PP
\fBsd_pidfd_get_owner_uid()\fR,
\fBsd_pidfd_get_session()\fR,
\fBsd_pidfd_get_user_unit()\fR,
\fBsd_pidfd_get_unit()\fR,
\fBsd_pidfd_get_machine_name()\fR,
\fBsd_pidfd_get_slice()\fR,
\fBsd_pidfd_get_user_slice()\fR, and
\fBsd_pidfd_get_cgroup()\fR
were added in version 253\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1), \fBsd-login\fR(3), \fBsd_session_is_active\fR(3), \fBgetsid\fR(2), \fBsystemd.slice\fR(5), \fBsystemd-machined.service\fR(8)
